Main bore knurl

Has anyone ever seen a main bore that has been knurled? A friend has a D1VE block that when taken apart for the first time found knurling in the main bore. His engine builder said Ford had some that were slightly over-bored at factory and this is how they corrected it, told him it would not hurt anything. Just curious, I have never seen it before.

I've heard of it being done to repair mains, Probably pretty old work, haven't heard of any one doing it nowdays.

But from my understanding it works if you can't find a block.

why not they use to knurl pistons to tighten them in the bores, I have seen punch dimples in some main saddles, I have even seen a small slice of paper behind main bearings to snug up the fit.

I don't see any reason it would be a problem, I thought it was funny that it probably was done at the factory since it had never been apart. You are right about pistons being knurled, it used to be pretty common along with valve guides I don't think it is done much any more.

the Coug wrote:why not they use to knurl pistons to tighten them in the bores, I have seen punch dimples in some main saddles, I have even seen a small slice of paper behind main bearings to snug up the fit.

I have seen and done the paper deal back in the 80s I was show by a old timer it worked but I wouldn't subjest it in a high prefromance engine.

69F100 wrote:

the Coug wrote:why not they use to knurl pistons to tighten them in the bores, I have seen punch dimples in some main saddles, I have even seen a small slice of paper behind main bearings to snug up the fit.

I have seen and done the paper deal back in the 80s I was show by a old timer it worked but I wouldn't subjest it in a high prefromance engine.

My father and I pulled a 390 out of a car it had a slight piston knock so the lady insisted we freshin it. we did and found a piece of paper under the mains. was there from the factory cuz this lady bought the car new, and we did all the maintinance on it...the piston had a crack in the skirt.

I not sure if ford did it but the old timer was a old ford machanic he told me it was just one of the tricks he had learned along the way.My Dad was a shop foreman back in the 60s and early 70s for ford.I will ask him about it when I talk to him tomorrow.